Using this Bosch laser measure is simple. First, insert the two AAA batteries. To take a measurement, press the measuring button. The real-time measurement mode will immediately show you the accurate distance. If you want to round the measurement result, use the rounding button to choose the desired precision from 1/2 In. up to 1/32 In. Use the click wheel to navigate through different settings and functions. When working in low-light conditions, the bright graphic display will make it easy to read the measurements. As for maintenance, keep the laser measure clean. Avoid exposing it to extreme temperatures outside the operating range of 14° F / -10° C to 104° F / 40° C. If the laser measure gets dirty, use a soft, dry cloth to clean it. Also, when not in use, store it in a safe place, and it'll fit nicely in your pocket for easy portability.